There are some cool Babbage-related meccano models here: http://www.meccano.us/

One of them is a "barrel" for the Analytical Engine: http://www.meccano.us/analytical_engine/index.html

There are also fully working models of the Difference Engine e.g. http://www.meccano.us/difference_engines/rde_2/index.html although I think they had to make some modifications due to the limitations of Meccano!